Atascadero Area Subbasin SGMA Support

In collaboration with GEI Consultants, GSI is helping the Atascadero Area Subbasin GSA develop a groundwater sustainability plan (GSP) to help manage groundwater resources under the Sustainable Groundwater Management Act (SGMA). The GSA represents the City of Atascadero, Templeton Community Services District, City of Paso Robles, and County of San Luis Obispo.

The first step in this work has been to help the Atascadero Mutual Water Company and Templeton Community Services District apply for a basin boundary modification with the California Department of Water Resources (DWR) to separate the Atascadero Area Subbasin from the larger Paso Robles Groundwater Basin.

GSI staff members provided the technical support to assist with this basin boundary request, and when DWR initially declined the application, GSI met with DWR staff in Sacramento to appeal the decision. DWR then approved the formation of a new Atascadero Area Subbasin; this was one of the few boundary modifications approved by DWR on a scientific rather than jurisdictional basis.

The decision gives the GSA more direct control over how it will manage its groundwater resources going forward. As the GSA begins its GSP development efforts, GSI will be providing the geologic and hydrogeologic technical expertise to ensure the sustainable use of shared groundwater resources.

GSI's work involved:

• Providing technical support to assist with a basin boundary request.
• Meeting with DWR to appeal its initial decision, leading to a successful approval based on scientific evidence that the Rinconada Fault creates a significant barrier to groundwater flow.
• Supporting GSP development efforts.